Forge heat treat on cpm d2.

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This needs a preface. I know d2 is not an ideal steel to heat treat in a forge. I'm new to making knives I'm using what I have. As soon as I can make, or buy a kiln I will.

Also, I'm only posting this because someone I was had a conversation with on Instagram told me to. I have a feeling he wanted me to post this so I could be ridiculed for using a forge. That's fine.

Anyway the main event. I've been making knives with a2, and cpm d2. Someone on the internet said I should do a break test on one of the knives, because they are probably terrible. So I did the heat treatment I've been doing on the cpm d2, and broke one.

Capturing this in scale, and actually showing the details is really hard. Especially for someone as bad at taking pictures as me. I did my best to show what the eye sees. Then zoomed in, took some with a macro lense, and finally took a picture with my microscope at 120x (it was NOT easy with the microscope I have).

Reddit - Dive into anything

www.reddit.com www.reddit.com

Sorry I don't know how to post pictures here. This is my first post.

To my eyes it looks completely smooth where it broke, and it seems like very fine grain. But I'm not an expert.
 
To post an image, right-click on the image on the site where you host it, select "Copy image address" from the menu. Then, click the image icon on the editor tool bar, select the "By URL" icon that looks like a chain link and enter the link. I've added one of your images below using this method.

I would buy some different steel for heat treating in a forge and save the D2 for when you have the capability to heat treat it properly, or maybe send it out for heat treat.

haa8w3a1x9i81.jpg
 
That was with a macro. I can't see that with my naked eyes. I'm doing this on mobile so I'm having a hard time getting these formatted

*edit the image I'm talking about is awaiting moderator approval

*edit 2: just click the reddit link. It's going to be a pita to post them all in this thread.

I'm guessing the microstructure (well what you can tell about it from breaking it and looking at it) is bad. From the response.
 
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The microstructure is not your worry with D2 and a forge. D2 benefits greatly from a very precise temperature, for an extended time, 20-30 minutes. Short of that level of precision, you probably would have been better off with a simple carbon steel.
Wait for your oven, get some stainless foil and quench plates, and save your tool steels for when you can optimize their strengths.
 
DevinT said:
What makes you think this can be done in a forge?
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Well the temperatures, and times seemed doable to me. I watched it with an infrared thermometer the whole time, changed its position when it was about to get hotter than I wanted, or colder. Turned the gas up or down.

My logic was a heat is heat, and if steel could be held in a certain range it would react a certain way. I guess I'm incorrect.
 
Keith Nix said:
The microstructure is not your worry with D2 and a forge. D2 benefits greatly from a very precise temperature, for an extended time, 20-30 minutes. Short of that level of precision, you probably would have been better off with a simple carbon steel.
Wait for your oven, get some stainless foil and quench plates, and save your tool steels for when you can optimize their strengths.
Click to expand...
I have stainless foil and quench plates. I did my best to hold it at around 1950 for 20 minutes, with a 1400ish degree preheat (at least as close to that as can be done with what I have) quenched in dry ice cooled aluminum bars on a vice, put it in a dry ice slurry.
 
From Roberts 1980, "Tool Steels 4th Edition" Pg 84, Chapter 3 "Testing of Tool Steels"


"The fracture will not generally represent a true reading of the austenite grain size on highly alloyed steels..."

(Like CPM D2)

"...in which all of the carbide is not dissolved during heat treatment; neither is it applicable to only partially hardened specimens in which excess ferrite or cementite or an appreciable quality of fine pearlite exists along with martensite in the quenched structure. It is also possible that retained austinite in large amounts may cause erroneous fracture readings. In these instances the constituents measured will interfere with the path of fracture and several grains may appear as one."



Translation: I wouldn't get excited about a good looking fracture test with CPM D2 as a sign of a badass HT and superior forge HT skills beyond what all these "nerds" that lack the "mad skillz" are going on and on about with a bunch of mumbo jumbo.


What seems like "mumbo jumbo" is pretty damn important.

Without proper temperature control on a steel like CPM D2 a maker is missing out on the really important features that make the CPM D2 perform good, such as using a proper soak at the right austenitizing temperature to truly make the name "CPM D2" live up to why it was desirable by name in the first place.

Oftentimes, people are chasing the names of steels but give little thought to the actual details that make the name of that steel worthy of being remembered for performance.



Blankblank said:
This needs a preface. I know d2 is not an ideal steel to heat treat in a forge. I'm new to making knives I'm using what I have. As soon as I can make, or buy a kiln I will.

Also, I'm only posting this because someone I was had a conversation with on Instagram told me to. I have a feeling he wanted me to post this so I could be ridiculed for using a forge. That's fine.

Anyway the main event. I've been making knives with a2, and cpm d2. Someone on the internet said I should do a break test on one of the knives, because they are probably terrible. So I did the heat treatment I've been doing on the cpm d2, and broke one.

Capturing this in scale, and actually showing the details is really hard. Especially for someone as bad at taking pictures as me. I did my best to show what the eye sees. Then zoomed in, took some with a macro lense, and finally took a picture with my microscope at 120x (it was NOT easy with the microscope I have).

Reddit - Dive into anything

www.reddit.com www.reddit.com

Sorry I don't know how to post pictures here. This is my first post.

To my eyes it looks completely smooth where it broke, and it seems like very fine grain. But I'm not an expert.
Click to expand...
 
Honestly the response I knew i would get. I guess, I'll just send them off from now on.

I know the break test isn't necessarily accurate, some knife maker on Instagram told me to do it, so I did. Then he told me to post the results here.

I know I why its important to have accurate temperatures. I just wanted to try. I guess I'm an idiot for thinking I could. Having someone else doing the heat treat, on a steel that already just requires stock removal makes it feel like I'm not really making a knife. I mean I really won't be at that point. The heat is such a big part of a blade.

I guess I just figured I could try my best to get the steel where it was saying it needed to be. I really feel stupid.
 
Blankblank said:
I have stainless foil and quench plates. I did my best to hold it at around 1950 for 20 minutes, with a 1400ish degree preheat (at least as close to that as can be done with what I have) quenched in dry ice cooled aluminum bars on a vice, put it in a dry ice slurry.
Click to expand...
A2 = 1750’-1775’f
D2 = 1850’- 1875’f

Austenitizing is the most important step in heat treating, you cannot control the temperature of a forge close enough for a proper treatment
 
Don't worry about it man, playing with steel is worth doing, even if you're doing it wrong.
Basically with any complex steel, you need really good temp control to make sure all the alloy elements get all "melted" into the steel.
If you don't your basically just paying more for carbon steel performance out of a "super steel".
 
No, the objective is not to bring you down or make you feel inferior.

I'm sorry.

Information is being shared out of love, not to tear you apart.

No one was born knowing any of this stuff.

Don't feel bad, I was the same way when I got started I wanted to heat treat without equipment and certainly learned I should have sent out at that time which I did.

You are most certainly still making the knife if you are sending it out for heat treatment.

It's better to outsource until you have the equipment or use a simpler steel, but even simple steel can benefit from that equipment and may even give some more complex steels a run for their money in some regards.


No one here is trying to rob you of the joy of doing heat treatment.

Yet, should we rob you of information you may not know?

Musashi once said,

"Truth is not what you want it to be, it is what it is, and you must bend to its power or live a lie"

No one is trying to hurt you, yet, no one is obligated to share either, if people are taking the time to share with you then it's taking effort which means they care.

Keep your head up.

Sending CPM D2 out for HT is not a lose in this situation. Its a win.


Blankblank said:
Honestly the response I knew i would get. I guess, I'll just send them off from now on.

I know the break test isn't necessarily accurate, some knife maker on Instagram told me to do it, so I did. Then he told me to post the results here.

I know I why its important to have accurate temperatures. I just wanted to try. I guess I'm an idiot for thinking I could. Having someone else doing the heat treat, on a steel that already just requires stock removal makes it feel like I'm not really making a knife. I mean I really won't be at that point. The heat is such a big part of a blade.

I guess I just figured I could try my best to get the steel where it was saying it needed to be. I really feel stupid.
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So can someone do 52100 in a forge? In your opinions? What is the limit? Something with chromium? Why should I use simpler steels in a forge? What would the point be? Those would still theoretically do better in a kiln too. Even though the austenizing temperature is lower it still would do better with a soak depending on what the starting structure of the steel is.
 
Blankblank said:
So can someone do 52100 in a forge? In your opinions? What is the limit? Something with chromium? Why should I use simpler steels in a forge? What would the point be? Those would still theoretically do better in a kiln too. Even though the austenizing temperature is lower it still would do better with a soak depending on what the starting structure of the steel is.
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Basically, anything that requires a soak time of over a minute or two should be done in an oven.
The longer you're soaking a piece of steel at high temp, the more carbon you are "burning" out of the steel.
 
It's not just about temp control either... It's also convenience.

So I've got a vertical forge that I built that will hold within a couple degrees of the set point more or less indefinitely... Well at least until it runs out of gas.

So I've got temp control down, but here's the problem. The forge has a 2.5 by 2.5 inch opening, and no floor. So if I was to try to HT something complex, id have to figure out how to hold the blade in mid air for 20 min maybe. Plus with more complex steels, I have to eliminate oxygen somehow, because higher heats mean faster oxidization, and at 2000 degrees there just isn't going to be much left.
So that means a foil packet around the blade. And I only have maybe 3 inches on the diagonal to get the knife in and out of the forge.

I'm sure you are beginning to see the problems right?

An oven/furnace/kiln whatever you want to call it, is just the right way to do it. A forge is just harder to get an optimal HT in.
 
I want to clarify I typed that post before I saw yours DeadboxHero DeadboxHero .

Your post did make me feel a little better about it. I wouldn't care so much, but right now I'm literally putting everything I have into this. It's my dream, and I kept putting it on the back burner because I would tell myself "I don't have this", or "I dont have that" I'm literally living paycheck to paycheck working in the drug addiction industry during the week, and sharpening and fixing up knives for money on the weekends. Then basically every waking moment I'm not doing that right now I'm trying this knife thing. So the costs that go into starting this thing seem so insurmountable. It can be discouraging.

Ok. I'll send it out. I have some cpm 10v I haven't touched yet. I was doing the cpm d2 first to see what would happen.

I guess I should decide what to ask them to do with it. I was going to shoot for 1400 for 10 or 15 minutes, and then austenize at 1950 for 20 or 30 minutes, then plate quench with the dry ice cooled plate quench vise, then put it into the dry ice slurry. Temper 2 times at 350 maybe.

So maybe ask them to substitute liquid nitrogen for the dry ice, and ask them to do that?
 
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A.McPherson said:
It's not just about temp control either... It's also convenience.

So I've got a vertical forge that I built that will hold within a couple degrees of the set point more or less indefinitely... Well at least until it runs out of gas.

So I've got temp control down, but here's the problem. The forge has a 2.5 by 2.5 inch opening, and no floor. So if I was to try to HT something complex, id have to figure out how to hold the blade in mid air for 20 min maybe. Plus with more complex steels, I have to eliminate oxygen somehow, because higher heats mean faster oxidization, and at 2000 degrees there just isn't going to be much left.
So that means a foil packet around the blade. And I only have maybe 3 inches on the diagonal to get the knife in and out of the forge.

I'm sure you are beginning to see the problems right?

An oven/furnace/kiln whatever you want to call it, is just the right way to do it. A forge is just harder to get an optimal HT in.
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Don't get me wrong. I was never arguing in favor of a forge over an oven for any reason. It was more me saying that I was using a forge, because I didn't have another option. Besides sending it out, but I'm stubborn, so I wanted to try myself.
 
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